NFAULT

DRV8800/01

NFAULT

DRV8800/01

VDD

Figure 9-9. nFAULT as Wired OR

9.3.4 Electrical Considerations

9.3.4.1 Device Spacing

It is recommended that devices be connected as close as possible and with trace lengths as short as possible.

Doing this minimizes the potential of generating timing differences between devices. Although it may seem

like a harmful situation for the power stage, the DRV8800 and DRV8801 devices contain enough protection to

effectively deal with enable time skews from device to device. This consideration focuses on motion quality, as

total current needed for acceleration and proper speed control will only be available when all power stages are

brought online.

9.3.4.2 Recirculation Current Handling

During recirculation, it is not possible to synchronize all devices connected in parallel so that the current is

equally distributed. Also, during the asynchronous portion of the current decay, the body diode with the lowest

forward voltage will start conducting and sink all of the current. Said body diode is not meant to handle the new

increased current capacity and will be severely affected if allowed to sink current of said magnitude.

In order to assure proper operation when devices are connected in parallel, it is imperative that external schottky

diodes be used. These schottky diodes will conduct during the asynchronous portion of the recirculation mode

and will sink the inductive load current until the respective FET switches are brought online.

Schottky diodes should be connected as shown in Figure 9-10.

M

VBB

GND

DRV8800/01

DRV8800/01

DRV8800/01

VBB

VBB

Figure 9-10. Schottky Diodes Connection

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DRV8800, DRV8801

SLVS855K – JULY 2008 – REVISED MARCH 2021

Copyright © 2021 Texas Instruments Incorporated

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Product Folder Links: DRV8800 DRV8801